A 36-year-old Apple-1 personal computer, one of just six thought to be in working condition, sold for a record $374,500 at a New York auction today.

Also sold by Sotheby's Friday: A memo written by former Apple CEO Steve Jobs during his time at video game maker Atari.

The gavel price for the Apple-1, which included the buyer's premium -- the commission owed to auctioneer Sotheby's -- was nearly twice the top estimate of $180,000 and triple the low-ball prediction of $120,000.

It was a record for an Apple-1, the first computer from the company co-founded by Steve Jobs and Steve Wozniak. The previous record of $213,000 was set in late 2010 at an auction conducted by Christie's in London.

Friday's price was 76% higher than the 2010 Apple-1 sale.

Sotheby's did not reveal the name of the buyer of either the Apple-1 or the memo, and did not reply to questions Friday. The BBC, however, reported that a telephone bidder won the auction for the Apple-1.

The Apple-1, a circuit board hand-built by Apple co-founder Steve Wozniak, was made in 1976, and sold at the time for $666.66. About 200 units were produced, but by Sotheby's estimate, only 50 survive. Six, including the one sold today, are known to be in working condition.

Included with the Apple-1 lot was an original cassette interface -- cassette tapes were used to store programs and data -- and several manuals, including a rare BASIC user's manual.

The four-page Jobs-authored memo sold for $27,500, also significantly higher than the auction house's preliminary estimate of $10,000 to $15,000.

That memorandum and an accompanying one-page addendum were written by Jobs in 1974 during a short stint with game-maker Atari, and included his suggestions for improvements on World Cup, a coin arcade game of the time. The lot featured three original circuit diagrams drawn by Jobs in pencil and the one-page hand-written addendum.

Although both the Apple-1 and the memo sold for well above their estimates, neither came close to the $1.6 million paid by a Miami executive last year for the original contract that marked Apple's founding. Jobs, who died in October 2011, Wozniak and the lesser-known Ron Wayne drew up the contract in April 1976.

Sotheby's also handled the sale of the Apple contract.

It may not look like much, but this 1976 Apple-1 computers -- a circuit board -- just sold for $374,500, a record, at a Sotheby's auction. (Image: Sotheby's.)